Odhneripisidium australiense (Korniushin, 2000)

Diagnostic features

Ligament external, introverted, stretching toward ventral side of hinge plate, and elevated over dorsal margin. Principal anatomical characters as in Afropisidium are only one (exhalant) siphon present; absence of inhalant mantle opening and outer demibranch, inhalant opening merged with pedal slit due to loss of pre-siphonal suture; ventral pair of siphonal retractors well developed, placed at posterior end of pedal slit. Outer demibranch absent. Brood pouch localised dorsally, formed by 7 to 20 filaments, upper position of brood pouch. Lateral loop of nephridium clearly visible from dorsal side.

"Species is similar in shape to P[isidium] dammermani Odhner, 1940 from Sumba but differs in its regular concentric sculpture. Pisidium sundanum Rensch, 1934 from Java also has coarse sculpture, but is larger. The species differs from P. novobritanniae Kuiper, 1967 (from New Britain), by having a rounded shell and more pronounced sculpture." (Korniushin 2000). It reaches 2.2 mm in length.

Classification

Odhneripisidium australiense (Korniushin, 2000)

Common name: Pea shell, pea clam, pill clam

Class Bivalvia

Infraclass Heteroconchia

Cohort Heterodonta

Megaorder Neoheterodontei

Order Sphaeriida

Superfamily Sphaerioidea

Family Sphaeriidae

Genus Odhneripisidium Kuiper, 1962 (Type species Pisidium stewarti Preston, 1909).

Original name: Pisidium (Odhneripisidium) australiense Korniushin, 2000. In Korniushin, A. V. (2000). Review of the family Sphaeriidae (Mollusca: Bivalvia) of Australia, with the description of four new species. Records of the Australian Museum 52(1): 41 - 102.

Type locality: Dowah Creek upstream from the junction with Freshwater Creek, Crystal Cascades, west of Cairns, Queensland.

Biology and ecology

"Brood pouch placed dorsally, formed by seven to twelve filaments and containing two to six embryos.........Inhabits springs and small creeks that are well shaded by trees with the bottom covered by leaves and vegetation." (Korniushin, 2000). Suspension and deposit feeder.

Distribution

Northern Queensland near Cairns.

Notes

This genus was considered to be a subgenus of Pisidium by earlier workers and was treated as such in earlier versions of this key. Molecular studies (e.g. Lee and Ó Foighil, 2003) have shown that it is a distinct genus.

Further reading

Beesley, P. L., Ross, G. J. B. & Wells, A., Eds. (1998). Mollusca: The Southern Synthesis. Parts A & B. Melbourne, CSIRO Publishing.

Korniushin, A. V. (2000). Review of the family Sphaeriidae (Mollusca: Bivalvia) of Australia, with the description of four new species. Records of the Australian Museum 52: 41-102.

Korniushin, A. V. (2002). Morphological characters analysis, the intergroup phylogenetic relationships and possible outgroups of the family Sphaeriidae (Mollusca, Bivalvia).  Vestbuj zoologii 36(4): 3-22.

Kuiper, J. G. J. (1962). Note sur la systematique des pisidies. Journal de Conchyliologie 102: 53-57.

Lee, T. (2019). Sphaeriidae Deshayes, 1855 (1820). Pp. 197-201 in C. Lydeard & Cummings, K. S. Freshwater Mollusks of the World: a Distribution Atlas. Baltimore, John Hopkins University Press.

Lee, T. & Ó Foighil, D. (2003). Phylogenetic structure of the Sphaeriinae, a global clade of freshwater bivalve molluscs, inferred from nuclear (ITS-1) and mitochondrial (16S) ribosomal gene sequences. Zoological Journal of the Linnean Society 137: 245-260.